1. Field of the Invention
The present invention relates to an endoscope having an insertion unit to which a helical rotation member having a helical fin portion is attached and a helical rotation member that is attached to the insertion unit of this endoscope.
2. Description of the Related Art
For example, Jpn. Pat. Appln. KOKAI Publication No. 2005-253892 discloses an endoscope. This endoscope has an insertion unit that is inserted into a lumen and a helical rotation member having a cylindrical shape that is attached to an outer peripheral surface of the insertion unit so that it can freely rotate in a peripheral direction of a central axis of the insertion unit. Further, the endoscope has an outer magnet secured to an inner peripheral surface of the helical rotation member and a rod-shaped inner magnet arranged inside the insertion unit.
The helical rotation member has a main body portion that is extended along an axial direction of the insertion unit and an inner peripheral surface of the main body is appressed against an outer peripheral surface of the insertion unit and a fin portion that is arranged on an outer peripheral surface of the main body and is helically arranged in the periaxial direction of the insertion unit.
The outer magnet has a ring-like shape. The outer magnet is arranged on the main body portion of the helical rotation member. In the outer magnet, N poles and S poles are alternately arranged along a circumferential direction of the outer magnet.
In the inner magnet, one N pole and one S pole are arranged along a circumferential direction of the inner magnet. The inner magnet is arranged inside the outer magnet. The inner magnet is connected with a motor through a flexible shaft and rotated by the motor.
When the inner magnet rotates, the outer magnet and the inner magnet attract or repel each other, and thereby the outer magnet rotates. When the outer magnet rotates, the main body portion rotates. When the main body portion rotates, the fin portion also rotates, the fin portion engages with an inner wall of the lumen, and an insertion (propulsive) force or removal force acts on the insertion unit. As a result, the insertion unit moves forward or backward in the lumen. As the inner wall of the lumen, for example, a gathered and folded inner wall surface of a large intestine is shown.